The pair were the most expensive purchases for Daredevils at the IPL auction last month. Pietersen was bought for £900,000 in the auction in February, after the franchise used its Right to Match card. Karthik cost £1.2 million.

The season will be Pietersen's second stint as captain of an IPL franchise - the England batsman had captained Royal Challengers Bangalore for a brief period in 2009.

Pietersen, who transferred to Delhi Daredevils from the defunct Deccan Chargers in 2012, has scored 305 runs in eight matches for the franchise. Overall, Pietersen has 634 runs in 21 IPL games at 42.26.

He missed the last season due to injury was but was seen promoting the franchise during the tournament. Pietersen was one of the marquee players at the auction, after Daredevils decided not to retain any players, and was expected to attract interest in spite of the abrupt end to his international career earlier in February.

In 92 matches across six seasons, Karthik - who was part of the Daredevils' squad for the first three seasons of the IPL before moving to Kings XI Punjab and Mumbai Indians - has scored 1741 runs and was one of the leading run-getters for Mumbai in their title win last year.

Gary Kirsten, who was appointed the Daredevils coach in September last year, said the two players would have a positive impact on the team.

"I am looking forward to working with Kevin Pietersen as the captain of the Delhi Daredevils," Kirsten said. "It will be great to have him with us for the full duration of IPL and I have no doubt that he will have a positive and significant impact. Dinesh Karthik, who has been appointed as vice-captain, will also form part of the leadership team. He has a lot of experience of playing the IPL and he will offer valuable inputs into our game plans and strategies during the tournament."